Reproductive migration of the coconut crab Birgus latro

Abstract

Knowledge of movement patterns is essential in tailoring spatial conservation and management measures. Although populations of the coconut crab, Birgus latro, have been severely depleted in most habitats, there have been few serious attempts to manage the resources. Recently, spatial conservation (e.g. seasonal area closure) has been suggested as an effective tool for resource management. However, relatively little is known about coconut crab movements, especially reproductive migration. To determine the dynamics of the reproductive migration of coconut crabs, we investigated both male and female migration patterns during the reproductive season in Hatoma Island, southwest of Japan. Both females and males migrated between inland and coastal areas during the reproductive season. Observed female seaward and landward migrations were temporally coincident with their reproductive activities (egg extrusion and larval hatching). Observed temporal-spatial distribution of males would be shaped by temporal variations in expected future mating opportunities within the reproductive season and male reproductive strategy in response to these variations.